Most state-of-the-art bipedal robots are designed
to be highly anthropomorphic and therefore possess legs with
knees. Whilst this facilitates more human-like locomotion, there
are implementation issues that make walking with straight or
near-straight legs difficult. Most bipedal robots have to move
with a constant bend in the legs to avoid singularities at the
knee joints, and to keep the centre of mass at a constant height
for control purposes. Furthermore, having a knee on the leg
increases the design complexity as well as the weight of the leg,
hindering the robot’s performance in agile behaviours such as
running and jumping.
We present SLIDER, an ultra-lightweight, low-cost bipedal
walking robot with a novel knee-less leg design. This nonanthropomorphic straight-legged design reduces the weight of
the legs significantly whilst keeping the same functionality as
anthropomorphic legs. Simulation results show that SLIDER’s
low-inertia legs contribute to less vertical motion in the center
of mass (CoM) than anthropomorphic robots during walking,
indicating that SLIDER’s model is closer to the widely used
Inverted Pendulum (IP) model. Finally, stable walking on
flat terrain is demonstrated both in simulation and in the
physical world, and feedback control is implemented to address
challenges with the physical robot.